1. Field of the Invention
The present invention relates to skateboard type devices for recreation and athletic training. More particularly, the present invention relates to wheeled devices which reproduce faithfully the sensation of using a snowboard, a mono ski or ski.
2. Brief Description of the Background Art
Recreation devices for gliding across various surfaces are well known. These devices include, for instance, water skis, inner tubes and the like for traversing water, and skis, snowboards, toboggans and the like for traversing snow. Lately, there has been a need to recreate these activities on dry land, specifically pavement or synthetic surfaces. Most notably, this need has resulted in the development of in-line skates to imitate ice skates, as well as the development of wheeled skis to imitate the movement of cross country skiing. However, there has not previously been a successful dry land imitation of the snowboard, monoski or downhill ski.
Previous attempts to create dry land monoskis have largely utilized skateboard technology. As is well known, skateboards utilize front and rear wheel assemblies (called "trucks") mounted on a substantially rigid elongate platform. The trucks each feature two wheels mounted with low friction bearings disposed on a metal axle housing. The axle housing is mounted on the underside of the platform fixed at a right angle to the longitudinal axis of the platform at a fixed distance therefrom. Although the axle housing is fixed at 90 degrees to the longitudinal axis of the platform, the axle housing is spring biased so that it is nominally disposed parallel to the closest lateral axis of the platform. However, under stress, the lateral plane of the platform of the skateboard is permitted to rotate about the centerpoint of the axle housing in order to permit turning.
In practice, skateboards do not successfully mimic the dynamics of snowboards or skis. That is, snowboards, skis and monoskis are one track devices that turn primarily by edging, whereas skateboards are of necessity two track devices that turn by steering. For this reason, they are not generally usable as warm weather training aids for snowboarding athletes, nor are they especially enjoyable for recreation.
Other dry land monoskis have been less successful. For instance, U.S. Pat. No. 5,125,687 relates to a rollerboard for road skiing. The rollerboard has large wheels mounted along the central longitudinal axis with an outrigger wheel disposed axially therefrom. As described in the patent, the front wheel along the longitudinal axis pivots for steering when the rollerboard is leaned onto one of the outrigger wheels. In this configuration, although the rollerboard travels in a straight line as a one track device, it functions when turning as a two track device.
U.S. Pat. No. 4,887,824 teaches another rollerboard having two skateboard trucks mounted along the central longitudinal axis of the platform. The platform provides inclined planes along the left and right sides of the longitudinal axis with a single truck pivotally mounted on each inclined plane as an outrigger. U.S. Pat. No. 4,744,576 teaches a similar rollerboard in which the trucks mounted along the central longitudinal axis are pivoting and the outrigger wheels are nonpivoting.
U.S. Pat. No. 3,827,706 provides wheeled skis having wheels pivotally mounted along the central longitudinal axis of a platform with nonpivoting outrigger wheels mounted along parallel longitudinal axes. As depicted therein, the wheels along the central longitudinal axis extend further beneath the platform so as to prevent the outrigger wheels from contacting the ground until the skis are banked for turning.
U.S. Pat. No. 5,409,265 teaches a skateboard having ball rollers mounted along the central longitudinal axis with smaller diameter ball rollers mounted along parallel longitudinal axes.
U.S. Pat. No. 4,106,786 teaches a board device particularly for use on nonpaved inclines. The device features a platform having a nonpivoting central wheel with outrigger skids. By shifting the operator's weight forward or rearward, the skids can contact the ground, maintaining a substantially level footing surface while braking the device.